1. Technical Field
This invention relates to copolymers having amine functionality. More specifically, the present invention relates to homopolymers and copolymers having amine functionality, wherein the polymers contain a substantial degree of neutralization with an organic acid. The polymers are useful in providing color protection in laundry and textile applications.
2. Background Information
Fabrics and textiles can become soiled over time, requiring cleaning. Cleaning these fabrics and textiles removes dirt from the fibers; however, fibers can be dislodged from the woven and knit fabrics or textiles in the process, resulting in lint, fuzz, or pills that can remain on the surface of the material. Not only are fibers lost, the cleaning process can also remove at least some of the dyes, resulting in the fading of the fabric. Both losses are detrimental to the fabric and result in an undesirable appearance.
Detergents, therefore, are formulated with additives designed to associate with the fibers, and diminish the effect of wear, fiber loss, pilling and color-loss. An effective protective additive must (a) have the ability to associate with the surface of the fibers, and not be easily removed, and (b) not adversely effect detergency or cleaning properties of the detergent, i.e., not attract dirt and other soils back onto the fibers.
One method of associating the protective additive to the fiber is to make use of the anionic nature of the fiber. Additives containing cationic moieties are attracted to and associate with anionic fibers, thereby providing some protection to the fibers. Detergents containing linear polyamines are used in laundry detergent applications using this principal. The use of polyamines for this application is described in International Publication Nos. WO 99/14297, WO 00/49124, and U.S. Pat. No. 6,140,292.
International Publication No. WO 00/56849 discloses laundry detergent compositions having cationically charged polymers. The polymers are amine-containing homopolymers, copolymers, or quaternized derivatives thereof. This application maximizes the cationic component of the polymer, thereby increasing association between the polymer and the fibers. Anions are only disclosed in association with quaternized polymers. Unfortunately, cationic polymer additives also attract dirt. Therefore, dirt which has been removed from the laundry is attracted back to the cationic polymer and thus back to the clothes.
Another approach for associating a polymeric protective additive with fibers is to utilize the relative hydrophobic nature of the fibers compared to the aqueous environment of the wash liquor. Hydrophobic polymers associate with fibers and minimize exposure to the aqueous environment. On the other hand, polymers having a high hydrophilic character, such as many of the polyamines and poly amino acids described in the art, associate with the aqueous wash liquor, and do not deposit well onto the surface of the fibers. One way to overcome this disadvantage is to form a polymer having quaternized amines, such as is disclosed in International Publication No. WO 00/22075. These polymers have a high hydrophilic character, but are attracted to fibers due to the strong cationic character. The negative side of the high cationic character is the attraction for dirt and thus poor redeposition properties.
Polymers having a high degree of hydrophobicity are difficult to synthesize since they tend to be water insoluble and come out of solution when placed into an aqueous solution. The solubility of the polymer can be improved by reducing the level of hydrophobe; however, this also reduces the positive fiber deposition properties associated with the hydrophobe.
Polymers having a high degree of hydrophobicity are described in U.S. Publication No. 2003/00720950. The hydrophobically modified solution polymers can be used to provide color protection and anti-pilling properties to fabrics and textiles. The polymers contain at least 75 mole percent (mol %) of the hydrophobic monomer, and the hydrophobic amine monomer is neutralized to improve solubility.
Still, there is a need for a polymeric additive useful in protecting fibers during the cleaning process and having the proper balance between hydrophilic, hydrophobic, and cationic components, thereby providing excellent protective properties to fibers while minimizing the negative effect on redeposition properties associated with cationic character. While not being bound to any theory, it is believed that the hydrophobe serves to minimize the interaction of the amine functionality with surfactants typically found in a detergent. The copolymer should balance the water solubility (amine groups) and the water insolubility (hydrophobic groups) on the polymer molecule in order to optimize desired properties.